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[Nadaka]

And of course anyone working on a moonbase for an extended period of time would quite literally be unable to come home again. Or go anywhere else, at least on a ship that pulls much acceleration. So yeah, they'd have to be either very well paid, very adventurous with no family or friends that they cared about, or convicts.

There is an easy solution to that bone and muscle strength loss due to low g environments. Artificial gravity. Build a circular railway and put a portion of the colony in cars on that railway, then run that railway fast enough to bring the acceleration felt up to a reasonable level. Each colonist would spend a proportion of their day on that railway, more so in the weeks/months before returning to earth. As the colony grows add more rail cars until the train is the same length as the track.

[Starver]

Currently, ISS (and, previously, MIR) had exercise machines modified/made for zero-G use, and a mandatory regime of use.  Exercise suites and a similar compulsion to use them would seem to be a better value for money than building a track, given everything.  Especially the risk of a derailment causing problems for everyone sleeping on board at the time...

Fiction (even hard-science fiction) often has rotating quarters on long-term deep-space missions, and I'm sure that something like that would be necessary (although I'm not sure if we're that good, yet, of leak-proofing the connection between rotating and non-rotating segments for such extended periods.  I'd be tempted to make the whole craft rotating around its fore-back axis (and making sure that the resulting stresses were more than manageable, with a good tolerance) except for the difficulty in overcoming the gyroscopic effect when the facing direction needed to be changed, and perhaps an amount of Coriolis-based confusion by those on board.

I don't immediately know if The Voyager (from 2001 AD) method is having the living centrifuge within the air-sealed environment (or perhaps a low-pressure secondary hull, to make the air-seal engineering less problematic), but that might be the way.

But (however you do it) you can't really have an Apollo-diameter ship generating Earhlike, Mars-like or even Moon-like gravity without severe gradient effects, it has to have a bigger radius/arm-length.  One reason you need more than just some refurbished (and flushed!  ..and reinforced!) Shuttle External Fuel Tanks for living quarters, and one reason you need bigger components (or assemblies), one reason for the Moon base factories (whoah, back on topic?  ...not for long).

But for the Moon, 1/6th g working seems good enough to me.  Fairground-style g-increasing sleeping quarters may be the necessary answer (but I'm still dubious of certain mechanical breakdowns on the equipment being used) and could be sited completely within air-filled areas to avoid the revolving seal problem (or entered by a docking ring, while stationary, and disconnected to spinning up and reconnected once spun down after the good night's sleep... as, unlike the spacecraft, there's a nice solid planetoid beneath them to push and pull the rotational velocities against wile spinning up and down).  And would not need to be anything as large/fast as space-borne solutions are to merely add (at an angle to the normal) gravity up to sufficient 'g' for health reasons.  But I'd go for larger-and-slower to avoid the (perhaps get-used-to-able) angular effects.

Or stick with the exercise suites.  More studies need to be done, I suspect.  (Not that I've sought full access to the current space-studies, either but studies in 1/6th g really still need to be done on top of that to properly assess the differences between artificial-g in zero-z and artificial-g in low-g.)

[PTTG??]

Now that's a plan! I've done the math- solar microwave sats are currently, counting solar panel inefficiencies, microwave recttenna inefficiencies, and launch costs, combined with an expected operational lifetime of 50 years or so, if not more... just about equal to simple solar panels on a dollars-per-megawatt basis.

If you lower the price of launch significantly, then it would actually be cheaper to put these things in orbit.

If they're in geosynchronous orbit, then there'd only be a 17-minute downtime (if I remember correctly) when it passes through the earth's shadow.

Only problem is for every km2 of solar you need a similar amount of space dedicated to rectenna, but luckily those are just a net of conductive wiring. You can hang it over a farm field and not impact the crops.

[10ebbor10]

Now that's a plan! I've done the math- solar microwave sats are currently, counting solar panel inefficiencies, microwave recttenna inefficiencies, and launch costs, combined with an expected operational lifetime of 50 years or so, if not more... just about equal to simple solar panels on a dollars-per-megawatt basis.

Way to optimistic. I'd be suprised if those solar panels functioned longer then 15 years. Earthbased  solar panels live about 20- 40 years, and Space isn't exactly a friendly environement.

There might be a solution for the transport problem though. NASA is currently researching a way of using a really big laser to propel a rocket from below. This means you need to take way less fuel on board, making your rocket lighter and cheaper.

[Andrew425]

Its chicken and egg for outer space industry really, as has been said. Sure, its much cheaper to build in space... but apart from building factors in space, what demand is there for actually building in space? currently very little.

http://www.spacedaily.com/reports/More_Than_1200_Satellites_To_Be_Launched_Over_The_Next_10_Years_999.html

Invest 400 billion in a moon colony and start building all our satellites up there.  In 20 years you've repaid your investment and you have a moon colony. 

Even better, you can probably lower the launch costs and increase the number of satellites that we use, increasing the size of the market.  If launch costs get low enough, you can start building microwave relay solar power satellites and start catering to the earth's vast energy market.

Investing 400 billion dollars would give us a base for 4-5 people. The ISS has a crew of 6 people orbiting earth, it's cost to date is 100 billion.

Do you guys realize how much work goes into making anything? It takes thousands of people to build something as technologically simple as your car. That means you would need to take the current manufacturing population that makes satellites and send them all up into space. Which would be tens of thousands of space ships. Which would be horrendously expensive. Their is no such thing as a "Space ship factory" what it is is hundreds of specialised factories all working to make single parts. You'd have to have a factory to produce things as simple as nuts and bolts. To make anything of this magnitude economically feasible you'd have to have each factory staffed by a lot of people. (Who you have to feed, clothe, bathe and find a place to sleep) So the upfront cost would bankrupt the United States. And what would it get it? Factories that cost many times greater then those on earth. Plus you would need to have hundreds of miners to produce the amount of material needed, smelters to smelt it into something useable. All which can be done on earth.

I'm all for a moon base, it's just not reasonable to have one that has more then 20 people.

[Nadaka]

Andrew425: spaceship parts are not mass produced in specialized factories. Nearly every structural part is made in a small shop with similar types of equipment. Precision lathes, programmable guided path milling machines, injection or vacuum mold machines, etc. These parts are then hand assembled in a clean room. With enough automation, it would be possible to build nearly any kind of equipment on the moon nearly unsupervised.

[Eagleon]

I raise you rapid prototyping equipment, remote extraction, and more than a hobbyist level of interest for it. If a bunch of engineering students can make a 3d printer for plastics that can build most of its own parts (sans high-heat and electrical components), imagine what could be done with an actual budget. Most of the personnel involved with the automotive (and satellite, thanks to a few standardized parts) industry are necessary because of an assembly-line volume of work - it does not take an entire factory to make nuts and bolts, it takes an entire factory to make nuts and bolts in a profitable way in the current market. It also doesn't take a labor force of miners and foundry workers to extract and smelt the amount of ore needed for a nut or bolt, it takes that many because they're supplying metal for every industry imaginable.

By comparison, if you have to wait half an hour for a glorified RC-car with kung-fu grip to trundle over to your solar furnace to set an ingot into your only bolt-mold, it's still cheaper than sending one bolt to the ISS.

Fake edit: ninjaed, curses.

[10ebbor10]

Problem is that your base would need to be self assembling repairing and maintaining and would be a quite a lot more complex then a cheap 3 d printer. While I don't doubt that people could pull it of If give enough money and time, there's a fairly good chance of a single undetected malfunction bringing down the whole system. Also moon dust is pretty mean on precision systems. (It's electrically charged and sticks to lot of things. 

Also, another problem that seems to be disregarded way to much. The moon lies outside the earth's magnetosphere. Which means no protection from solar winds and other types of radiation.
While your underground base would probably be fine, severe malfunctions can and will occur to all above ground electrical equipment.(Like solar panels).

[Starver]

I'm all for a moon base, it's just not reasonable to have one that has more then 20 people.

I'm obviously remaining at odds with people, because IMO, it's not reasonable to have one with less than 20 people.

It's certainly a different quantity against which the 'reasonableness' is benchmarked, of course.

[mainiac]

Their is no such thing as a "Space ship factory" what it is is hundreds of specialised factories all working to make single parts. You'd have to have a factory to produce things as simple as nuts and bolts.

I've worked in a factory making bolts.  Well I use the term factory very loosely here because I was making a specialty item (runs of only a few thousand) and I was the only one working on that product line.  Most bolts aren't made the way of a single trained worker churning out a few thousand using high end machinery over the course of a week.  But you can do it if the large scale manufacturing lines dont exist for the exact bolt that someone needs for some reason.  The point here is that you design your manufacturing process around your constraints and objectives, not the other way around.

A lunar factory would look very little like an earth factory.  People have already pointed out things like automation, but I'll do you one better.  Why on the moon would the entire colony need to use a single bolt at any point in the construction process of a satellite?  Stuff built on the moon can be unimaginably crude but still work because it's already outside the earth's gravity well.  So don't use bolts when it's easier to weld.  Don't use high quality alloys when stuff barely better then slag will do.  The crudest construction will work nearly as well as the best once it's already in orbit so we should go ahead and construct stuff crudely!

If the lunar factory can even make one satellite every three days and successfully launch them, it can cover earth's current telecommunications needs.  Even if it's just covering the bulky parts of the construction (the radiators, structure and maneuvering fuel), that's a huge cost savings compared to earth launches.

The other thing is that the lunar colony can continue to build it's own facilities allowing for growth by just sending more astronauts.  Hydroponic greenhouses in particular strike me as a very useful structure that can be built with lunar glass, steel and water with only the trace elements and seeds being sent from earth.

[Eagleon]

Problem is that your base would need to be self assembling repairing and maintaining and would be a quite a lot more complex then a cheap 3 d printer. While I don't doubt that people could pull it of If give enough money and time, there's a fairly good chance of a single undetected malfunction bringing down the whole system. Also moon dust is pretty mean on precision systems. (It's electrically charged and sticks to lot of things.

Actually I was more thinking of remote operation for the bulk of assembly work, for that exact reason. We're a ways off from self-adaptive and repairing systems for a system this complex. Hiring a foundry worker to operate certain machines from Earth, even at a premium wage, would be cheaper than putting them on the moon, and you'd still get the work done at the same rate. Remote repairs would be tricky, but nothing impossible - we have robotic surgeons, the only reason we don't have robotic electricians is because hands are cheaper to come by. Granted, moon dust is always going to be an annoyance. Hardier mechanical systems, particularly methods of locomotion adapted to reduce the build-up, are a must.

For a long time, it'd be doing the bricklaying for a much larger facility, building the machines that make the machines to make more complex parts. Boring, I know, but a sight better than spending hundreds of billions of dollars to drop a couple of under-equipped astronauts in a trench and hope for the best. On the plus side, it's scalable as interest increases - new facilities with precious Earth-precision equipment could be introduced to divide work and make the system more resilient.

The core of what we'd need is a solar furnace with a couple of different separation and processing methods, which requires minimal to no sensitive electronics, but would admittedly probably be heavier than we'd like; a good assortment of mobile manipulators, which wouldn't have to be terribly complex at first; a hardy excavation tool for finding and returning ore, which would double to build entrenchments for more delicate equipment such as the aforementioned, probably the heaviest of the bunch; a moveable power station and short range communications relay for recharging the robots; and a plastic printer with a supply of thermoplastic for structural components while the infrastructure for replacing them with aluminum, titanium, or glass/ceramic is resolved. After that, you could build molds for casting any number of parts, spools and extrusion plates for making wire for motors (probably kick-started with a little mechanical oomph from the excavator), and additional solar furnaces with some polishing equipment.

[MonkeyHead]

The fact that moon dust has a residual charge could make it easier to deal with than dust that isnt - all you need is a relatively well designed electrostatic attractor (not dissimilar to the carbon scrubbers in furnaces) to "hoover" it up and keep it away from sensetive engineering.

[Blade Master Model 42]

I'm all for the idea of a moon base. I want us exploring the solar system and plundering it's natural resources, seeing as no one else is using them.

[Il Palazzo]

This whole conversation reminds me of the Global Village Construction Set. Make it Moon Village CS instead, put some more people to develop the designs, and I can see how a few selenauts could by themselves construct a base and basic industry on the Moon, with little supplies required from Earth.

[mainiac]

Cool!